Doppler Spectrum as the Perspective Instrument for Detection of the Ice Cover

At the radar probing of the sea surface, the main informative parameter is the backscattering normalized radar cross section (NRCS), which does not always make it possible to unambiguously determine the kind of scattering surface (ice/water). In this paper, we discuss the possibility of using the Doppler spectrum (DS) of the reflected radar signal to solve this problem. For the first time, a semi-empirical model of the DS of a microwave radar signal reflected by an ice cover was developed for a radar with a wide antenna beam mounted on a moving carrier. Radar is measuring at the small incidence angles (0° – 19°). Several configurations of the antenna system were considered and it was shown that it is necessary to use a wide or knife-like (in incidence angle) antenna beam for measurements. Calculations confirmed the assumption that, when measured from a moving carrier, the DS is a reliable indicator of the transition from one kind of scattering surface to another. The shift and width of the DS, as well as the skewness and kurtosis coefficients for the shape of the DS can be used as criteria in a selection algorithm.